Pump for hydraulic jacks



' H. E. PAGE April 20,1948.

PUMP FOR HYDRAULIC JACKS Filed Oct. 2'7, 1944 2 Sheets-Sheet 1 #4 I -f\ I 1 fi w I L If ,4 V D l /2 l 3 4 3 INVENTOR.. f; 7 7 E a :Henbert BY April 20, 1948. H. E. PAGE PUMP FOR HYDRAULIC JACKS 2 Sheets-Sheet 2 Filed Oct.' 27, 1944 Patented Apr. 20, 1948 UNITED STATES PATENT OFFICE PUMP FUR HYDRAULIC JACKS Herbert E. Page, Alhambra, Calif.

Application October 2'7, 1944, Serial No. 560,572

6 claims. (01. 103-37) My present invention relates to hydraulic pressure-generating devices, such as hydrauliciacks.

Conventional hydraulic jacks have a work-lifti'n'g piston and a pumping piston for generating the hydraulic pressure. Heretofore the pumping pistons have extended from the pumping cylinder, where they are "connected to the actuating levers. construction has presented certain objections. For instance, the protruding end of the pumping piston, upon receiving a blow from any heavy object, often becomes bent and inoperative. Moreover, it is relatively easy for dirt, water and other foreign elements to work into the pumping mechanism past the packing, where it scores or otherwise damages the piston cylinder. Also in such conventionally constructed jacks, if any high pressure leak should develop past the packing, valuable hydraulic fluid is lost, requiring frequent refilling of the fluid reservoir "and the escaping oil tends to collect on the exposed parts and collect dust.

An object of my invention is to rovide a hydraulic which eliminates those difilculties by placing the pum -operating mechanism and pumping iston "within a closed chamber or within the fluid reservoir itseliso that they are not exposed and so that an fluid which might escape under pressure from the pumping cylinder merel returns to the reservoir and is not lost.

Another of the principal objects of my invention is to provide a pump-actuatlng'means which may be optionally operated to rovide double aclien for establishing quick contact of the lifting piston with the work to be lifted.

M invention has still other sub rdinate advantages and features of novelt which those familiar with the art will readily understand from the following detailed description or one embod'irnent which I have chosen for explanatory purposes, it being understood, of course, that withthe broader scope of the invention as defined by the a ended claims, the invention may be embodied in other physical forms. For purposes of the following description I shall refer to the accompanying drawings, in which:

Fig. 1 is a plan section;

Fig. 2 isa section on line 22 of Fig. 1;

Fig. 3 is a section on line '33 of Fig. 1;

Fig. 4 is a section on line E4 of Fig. l; and

Fig. 5 is a view taken on line 5-5 of Fig. 1.

2 cylindrical wall 12 around the cylinder ll) provides an annular auxiliary reservoir R which communicates with the main reservoir R through a port I' l.

Pistons l5, l6, respectively, are reciprocally mounted in cylinders 6, I, being urged outwardly of the respective cylinders by compression springs ll, [8. Pressure chambers I9, 20, respectively, are provided between the inner ends of the pistons 15, It and their respective cylinders.

A V work-engaging piston 25 is reciprocally mounted in cylinder lll, its inner end providing, with the bottom of the recess l l, a pressure chambet-25.

Valve chambers 30, 3! are provided in the body, there being a ballcheck valve 33 seating towards the reservoir in chamber 3'1 to control the inlet from the re ervoir, the valve being urged seated by a spring 34. A ball check valve 35, urged seated towards chamber 3| by a spring 36, controls now of fluid between chamber 3l and chamber 2E through a port 38. A screw plug closes the outer end of valve chamber 30.

Valve chamber 3| communicates with chambers I9, 20 through connecting ports 39, 40. To release fluid from chamber 26, as is necessary when it is desired to lower the jack, I provide a needle valve 42 threaded through an opening 43 in the body and cooperating with one end of port 38.

For actuating the pistons l5, I5 I provide a transverse shaft 50 which is journaled at its ends in the body and has secured thereon two collars 51, 52, Collar 5| presents a, single lobed cam 53 and collar 52 presents a double lobed cam 54.

To the outer end of shaft 50 I secure a socket member 60 presenting oppositely opening sockets BI, 62 and a crank-receiving socket 63. An actuating lever may be inserted in either of the sockets Bl or '62, or, for rotation, a crank may be.

inserted in socket 63.

It will be observed that on each suction stroke of the pistons l5, IE, or either of them, fluid is drawn from the reservoir past check valve 33 and Referring to the drawings, I show a body 5 providing a fluid reservoir R and a pair of cylinders t, l of relatively diirerent diameters. A tubular member or cylinder I0 is threaded at its bottom end m a recess l l in the body, and a through ports 39, 40 into chambers l9 and 20, and on each pressure stroke the fluid is forced from, the chambers l9 and 20 past check valve 35 and through passageway 38 into chamber 26 to raise the piston 25.

With the socket member 00 and shaft 50 in the position shown in the drawings, if the actuating lever is oscillated about the are denoted by the arrow 10 in Fig. 5, only the top lobe of cam 54 will engage piston l6 on each forward movement of the lever to move the piston inwardly of its cylinder, the piston being returned by its spring I8. However, if the actuating lever be oscillated about the 180 are indicated by the arrows HI, ll, on each forward stroke the top lobe of cam 54 will operate piston l6 while on each backward stroke the bottom lobe of cam 54 will engage piston l6 and the single lobe of cam 53 will simultaneously engage piston l5. r, upon full rotation of the shaft all three cam lobes will engage and actuate the pistons. If the shaft 50 is rotated about 180 to reverse the relative positions of the sockets BI, 62 from the positions shown in the drawings, a, movement of the actuating lever about the are denoted by arrow 10 will cause cam lobe 53 to engage piston l5 and simultaneously will cause one lobe of cam 54 to engage piston l6.

Thus, for effecting relatively rapid protraction I of the piston the operation of the cams will be as last above described, or the shaft may be rotated about full revolutions. When the load is contacted or slower operation is desired, the shaft may be returned to the piston shown in the drawings and the actuating lever operated about the are denoted by the line ill.

I claim:

1. In a hydraulic pressure-generating device, a body providing a closed compartment and a pair of parallel cylinders opening into the compartment, a pumping piston reciprocally mounted in each cylinder and having its outer end exposed to the compartment, the inner end of each piston forming with the inner end of its cylinder a pressure-generating chamber one of the cylinders and its corresponding piston being of larger diameter than theother cylinder and its corresponding piston, a pair of cam members in the compartment journalled in the body for rotativ-e camming engagement with the outer ends of the pistons to move the same in their pressure strokes, means for actuating the cam members, spring means cooperating with each of the pistons to move the same in its suction stroke, first valve controlled means for admitting fluid to the pressure-generating chamber upon each suction stroke of the respective pistons, and second valvecontrolled means passing fluid under pressure from the pressure-generating chambers upon each pressure stroke of the respective pistons.

2. The device of claim 1 wherein one of the cam members is disposed opposite the other cam member.

3. In a hydraulic pressure-generating device, a body providing a closed compartment and a pair of parallel cylinders opening into the compartment, a pumping piston reciprocally mounted in each cylinder and having its outer end exposed to the compartment, the inner end of each piston forming with the inner end of its cylinder a pressure-generating chamber one of the cylinders and its corresponding piston being of larger diameter than the other cylinder and its corresponding piston, a shaft in the compartment, said shaft being journaled in the body for rotation about an axis normal to the longitudinal axes of the cylinders, a pair of cam members on the shaft positioned to have c amming engagement with the outer ends of the pistons upon rotation of the shaft to impart the pressure strokes to the pistons, means for rotating the shaft, spring means cooperating with each piston to impart the suctionstroke thereto, first valve controlled means for admitting fluid to the pressure-generating chamber upon each suction stroke of the. respective pistons, and second 4 I valve-controlled means passing fluid under pressure from the pressure-generating chambers upon each pressure stroke of the respective pistons.

4. In a hydraulic pressure-actuated device,

pressure-generating means for supplying fluid under pressure at different volume-pressure ratios comprising a body presenting a fluid reservoir and a pair of parallel cylinders providing pressure chambers of relatively different diameters, a pair of pumping pistons mounted one in each of the respective cylinders and respectively having inner ends of diameters fitting and cooperating with the respective chambers, a cam shaft journalled in the body for oscillation about an axis normal to the longitudinal axis of the pistons, a pair of oppositely disposed cams fixed on the shaft for engagement with the outer ends of the respective pistons whereby to selectively move them inwardly in response to oscillation of the shaft, spring means cooperating with the pistons to move them outwardly of the cylinders, means for oscillating the shaft and valve controlled ports in the body providing controlled communication between the reservoir, the pressure chambers and a hydraulic pressure actuated device.

5. In a hydraulic pressure generating device, a body providing a closed compartment and a pair of parallel cylinders opening into the compartment, a pumping piston reciprocally mounted in each cylinder and having its outer end exposed to the compartment, the inner end of each piston forming with the irmer end of its cylinder a pressure generating chamber, a pair of cam members in the compartment journaled in the body for rotative camming engagement with the outer ends of the pistons to move the same in their pressure strokes, one of said cam members having a pair of oppositely disposed camming lobes for alternate engagement with the outer end of one of the pistons and the other of the cam members having but a single lobe disposed parallel with one of the lobes of the other cam member for engagement with the outer end of the other piston, means for actuating the cam members, spring means cooperating with each of the pistons to move the same in its suction stroke, first valve controlled means for admitting fluid to the pressure generating chamber upon each suction stroke of the respective pistons, and second valve controlled means passing fluid under pressure from the pressure generating chambers upon each pressure stroke of the respective pistons.

6. In a hydraulic pressure-generating device, a body providing a closed compartment and a pair of parallel cylinders opening into the compartment, a pumping piston reciprocally mounted in each cylinder and having its outer end exposed to the compartment, the inner end of each piston forming with the inner end of its cylinder a pressure-generating chamber, a shaft in the compartment, said shaft being journaled in the body for rotation about an axis normal to the longitudinal axes of the cylinders, a pair of cam members on the shaft positioned to have alternate camming engagement with the outer ends of the pistons upon rotation of the shaft to impart the pressure strokes to the pistons, means for rotating the shaft, spring means cooperating with each piston to impart the suction stroke thereto, first valve controlled means for admitting fluid to the pressure generating chamber upon each suction stroke of the respective pistons, and second valve controlled means passing fluid under 5 pressure from the pressure generating chambers Number upon each pressure stroke of the respective pls- 1,508,054 tons. 1,969,408 HERBERT E. PAGE. 2,040,667 5 2,172,103 REFERENCES CITED 2,312,304 The following references are of record in the 2313302 file of this patent: 2,327,787

UNITED STATES PATENTS 10 Number Name Date Numb? 1 1,016,692 Joyce Feb. 6, 1912 369, 6 1,502,195

Hicks July 22, 1924 Name Date Hopkins Sept. 9, 1924 Kramer Aug. 7.61934 Moulet May 12,". 1936 Kotaki Sept. 5;";1939 Anderson Mar. 2, 1943 Sobek Mar. 9, 1943 Heintz Aug. 24,1943

FOREIGN PATENTS Country Date Great Britain 1932 

